The device herein is used in connection with an air filter for an internal combustion engine. Said device indicates when said air filter has become so loaded with contaminants that the supply of air required by the engine for operating efficiency is not being drawn through the filter by the engine and that the filter requires cleaning or replacement.
Said device gives a continuous reading to indicate the build up of contaminants within the air filter to inform the operator of the condition of the filter. However, said device does away with guess work as to the time when cleaning or replacement of the air filter is necessary and thus provides for maximum use of the air filter. As to the same for cleaning or replacement of the air filter, the device herein gives a positive indication.
It is an object of the invention herein therefore to provide a device in connection with an air filter for an internal combustion engine to give a positive indication as to the need for cleaning or replacing the air filter.
It is another object of this invention to provide a device in connection with an air filter for an internal combustion engine to give a continuous visual reading as to the build up of contaminants within the air filter and to indicate the remaining use period of said air filter prior to cleaning or replacement.
It is another object of this invention to provide a device in communication with the air stream passing from an air filter to the air intake of an internal combustion engine to indicate the degree of contamination of said air filter with said device being readily adjusted to respond to the varying air requirements of different internal combustion engines.
It is also an object of this invention to provide a device as above indicated which is of simple construction and which is readily installed in operating position. More particularly stated, said device comprises a housing having an indicating member therein which is colored to be readily seen through the housing and which is carried upon a diaphragm which is of inverted cup shape in form with said diaphragm being supported in extended position by a helical spring adjusted to balance the pressure differential between atmospheric pressure upon the diaphragm and the partial vacuum drawn upon the other side of said diaphragm by the air intake stream passing from the air filter to the air intake of an internal combustion engine whereby when a sufficient supply of air is passing into the air intake of the engine from said filter the device gives such an indication by being inoperative and when an air restriction develops in the air filter resulting from a build up of contaminants therein said partial vacuum on the air line passing to the device from the filter increases causing the diaphragm to collapse or fold in upon itself and draw downwardly the indicator which it carries to give a visual reading of the build up of contaminants within the air filter and when said air filter is fully contaminated to the point that sufficient air supply cannot be drawn therethrough, then said diaphragm becomes fully folded in upon itself and said device gives such a reading indicating the need for cleaning or replacing the air filter.